Resistance unit



Se t, 16, 1930. G. J. 'MUCHER RESISTANCE UNIT Filed Sept. 9. 1926 INVENTOR 5207' e .fJ/fiucfizr ATTORNEYS K: Na Him. a w M Patented Sept. 16, 1930 .r i I 1 ,776,l9l}

UNITED STATES PATENT OFFICE GEORGE J. MUCHER, F BROOKLYN, NEW YORK RESISTANCE UNIT Applicationfiled September 9, 1926. Serial No. 134,442.

This invention relates to an improved rewith a base or shoulder 6 engaging the offset sistance unit and has for an object to pro- 1 onone side while a nut 7 engages the opvide an improved construction wherein a posite side and thereby locks the sleeve in maximum contact surface is provided for the position. This sleeve. accommodates a 5 resistance material. threaded shaft 8 to which a conductor 9. is 55 Another object of the invention is to proadapted to be secured when the device is in vide a resistance. unit wherein the resistance use. It will be understood that shaft 8, sleeve is formed of powdered or granular matter 5 and plate 8 are of metal whereby a good and-entirely enclosed, the enclosing casing connection is made with the casing 1. The

10 acting as a contact or connector. lower or inner end of the shaft 8 is provided 60 A further object of the invention is to with an annular-groove 10 whereby an anprovide a resistance unit using a resilient nular flange 11 is produced adapted to be powdered or granular resistance body, the passed through the aperture 12 in plate 13 structure being such that the parts may be and then moved laterally so that'the reduced 15 adjusted for compressing the resistance maneck 14: will snugly fit in the end of the slot 65 "terial' or reducing the pressure thereof for 15. This permits a quick and easy assemblage varying the action of the unit. of the shaft 8 and the compressing member A still further object is to provide a reor piston 16. The compressing member 16- sistance unit in which a compressible reis formed bythe plate 13, a packing member flo sistance body is provided and a substantially 17 and a plate 18. The packing member 17 fire-proof compression member used so as to may be any fibrous material, as for instance, cause the unit to properly function even when. ordinary felt. This is clamped properly in hot. position by the posts or spurs 19 which are In theaccompanying drawings preferably integral with plate 13, said posts Figure l isalongitudinal vertical sectional extending through the packing "17 and 75 View through a resistance unitdisclosing an through, plate 18 whereby when they are embodiment of the invention. upset for forming enlarged ends 20 the parts Figure 2 1s a sectional view through Figure are firmly clamped together. Plate 18 is pref- 1 on line 22. erablya disk and falls short of the casing 1.

Figure 3 is a top plan view of a modif ed The bottom ofcasing 1 is provided with an 80 2 "form of compressor to that shown in Figure 1. aperture 21 throughwhich the metallic screw l 4 is a Sectional View h g Figure 22 extends, said screw having acomparative- 11116 a the Same Showlng a p l g ly large head 23 fitting against the bottom 1 an annular p for expandlng plate 2.4,said bottom plate being of insulating 5 531d, material. An insulating washer 25 is ar- 85 Flgtlre an enlarged ilevatlon of h ranged exteriorlv of the casing 1 and is clampmg nng shown In Flgure Certaln clamped in position by a suitable nut 26 parts belng broken away whereby the screw 22 is firmly. clamped in Fi ure 6 is a view similar to Figure 1 eX- F place but 15' held out of contact with the 40 cept that it is on a reduced scale and shows casing 1. A nut 27 acts to lock nut 26 in g ggi i i gg umt Wherem place and also to clamp conductor 28 whereby.

Referrin to the accom an in drawin current may be allowed to pass through the b m i 1 i di g g i, fi device. Arranged betweenthe plate and which is preferably of thin metal. The upthe Qn held 23am! e p a 95 per edge of the casing 1 is turned over at 2 18 and Plate 2 7 a e$15t311ce fil WhPFh so as to pinch the. top plate 3, which top may be of any desired materlal which willplate has an apertured offset portion 4 acbe granular or powdered form and wh ch com modating the internally and externally will be more or less resilient so as to present threaded sleeve 5. The sleeve 5 is provided a proper resistance at all times and variabl? 100 resistance according to the density of the material.

The material 29 may be for instance, flaked or powdered graphite and finely divided mica or even asbestos. The graphite acts as a conductor while the mica acts as a resistance and also as resilient means for expanding or spreading the mass whenever permitted to do so. /Vhen the parts are in the position shown in Figure 1, the device presents a certain resistance; It the shaft or threaded rod 8 is rotated for moving the compressor 16 toward plate 24, the resistancematerial 29 would be compressed somewhat and the resistance of the apparatus will be changed. If shaft 8 is rotated in the opposite direction so as to relieve the pressure on the resistance material 29, said material will expand. by reason of the resilient action of the mica and being more expanded and open the resistance of the device will be changed again and will be greater than when the material 29 is compressed. It will be noted that the material 29 is in contact with casing 1 and, consequently, all electrical current must pass from the enlarged head 23 to the resistance material and from thence to the casing as well as to plate 18. In this way a uniform action and a highly eflicient device is presented.

Under some circumstances it is desired to operate the unit with an appreciable current and under some considerable heat. When this is desired, the compressor 16 is removed and a modified form of compressor16 is provided. The compressor 16 is provided with a plate 13 similar to plate 13 and with openings similar to openings 12 and 15. However, instead of havinga solid body of felt, a

.ring 30 of asbestosor other fire resisting fiber is provided and clamped in position by the plate 18, which plate is held in placeby.

the solid rin 31, said rin havin )ro'ectm o t: r; :9 portions 32 and 33 which are upset at the ends ,so as to form'enlargements 34 and 35 whereby plates 13 and 18 are properly connected together and properly grip the ring 30. Whenever desired, a fiat spring 51 is used. This spring is especially desired where the packing 30 is non-resilient or substantially non-resilient. The spring continually acts to spread or force out radially the packing 30 and thereby maintain a good'contact at all times with the walls of the casing 1 so that none of the resistance material can escape past the compressor. WVhen this compressor issubstituted for that shown in Figure 1, the device may be operated even though it becomes hot'as an appreciable. amount of heat I will not injureany of the parts.

In many cases a permanent and nonadjust able resistance is desired. hen thisis the case, the structure shown in, Figure 6 is used, saidstructure being similar to Figure 1 but not provided with the adjustable compressor. In this form-0t the invention, the casing 36 is turned over on top plate 37 through which the contact rivet 38 extends, said rivet having an enlarged head 39 and a small head 40, said small head clamping a connector 41 in place. An insulating plate 42 is arranged between head 39 and plate 37 and also an insulating Washer 43 is arranged between connector 41 and plate 37. This insulates the-head 39 from plate 37 and from casing 36. A similar structure is arranged at the opposite end of casing 36, namely, a contact rivet 44 is provided having a small head 45 for clamping the conductor 46 in place. The contact rivet 44 is also provided with an enlarged head 47 resting on the insulating plate 48. An insulating washer 49 is provided for insulating a conductor 46 from casing 36. A resistance filling 50 of the same kind as filling 29 is provided and is placed under the desired pressure when the device is manufactured so that the compactness of the material 50 will always remain the same and, consequently, the re sisting action will always remain the same i It will be noted from Figures 1 and 6 that the resistance material is always in contact -with the metal body or container 1 and, theretore, permits the heat generated to more rapidly become dissipated as the parts are metal and rapidly conduct heat. Thisrapid dissipation of heat permits a more efiicient action of the unit and particularly permits heavier currents to be handled with smaller units than would be the case it this dissipation of heat was not provided for. It will also be noted that in caseof a heavy overload, the metal casing provides an instant path for taking care of this overload so that the flow of current will not be stopped and the device will not be appreciably injured. By reason of the V substantially air-tight structure provided, the

resistance material is sealed against the action of the air and, consequently,'is practically humidity proof so that the action of the of said resistance body, and manually actuated screw means rotatablyconnected with 7 said compressor Without rotating the same.

2. A resistance unit comprisinga pair of contacts, one'contact being formedas an enclosing metal casing substantially air-tight.

and the other contact as a rod provided with an enlarged head, said head being positioned within the casing but out of contact therewith, a resistance body connecting directly the side walls of said casing and said enlarged head, said body being made of material which will vary its resistance according to its compression, a compressor for varying the den sity of said resistance material, and manually actuated screw means rotatably connected with said compressor for shifting the posi tion of the compressor without rotating the same.

3. A resistance unit comprising a pair of contacts, one of said contacts being formed as part of an enclosing casing, a granular resistance body arranged in the casing and connecting the side walls of the casing directly with the other contact, a com )ressor arranged'in the casing, and a threadec mem ber for moving said compressor in either of two directions for varying the density of the resistance material whereby the resistance action will be varied, said threaded member be ing rotatably connected with said compressor for moving the compressor without rotating the same.

4. A resistance unit comprising a pair of contacts, one of said contacts being formed as an enclosing casing, said casing having an opening at both ends, a second contact extending through one of said openings, means for insulating said second contact from said casing, a screw member extending through the other of said openings, a substantially granular resistance body connecting directly the side walls of the casing with said second contact, a compressor arranged in the casing and operatively connected with the screw member whereby when the screw member is caused to function the compressor will be moved toward or from the second contact for varying the density of said resistance body.

5. A resistance unit comprising a pair of contacts, one presenting a metallic casing and the other extending into said casing but insulated therefrom, a resistance body of compressible material arranged in said casing and in direct contact with the side walls of said casing and with said other contact, a compressor arranged in said casing with the periphery thereof continually in engagement with the casing. said compressor acting to compress and force the resistance body toward the insulated contact, and screw means carried by the casing for shifting said compressor, said screw means having a head rotatably connected with said compressor whereby the screw means may be rotated for shifting the position of said compressor without rotating the compressor.

6. A resistance unit comprising a pair of contacts, one contact presenting a casing and the other contact extending into the casing but insulated therefrom, a compressible resistance body arranged in the casing and in continuous contact with the walls of the casing and with the insulated contact, a compressor arranged in the casing for varying the density of said compressible resistance body, an end plate arranged at the end of the casing opposite the insulated contact, said casing having a turned over edge gripping and holding said end plate, a threaded member carried by said end plate and a threaded member carried by said compressor and engaging the threaded member carried by the end plate whereby as the threaded member carried by the compressor is rotated the compressor will be moved toward or from the insulated contact for varying the density of said resistance body.

GEORGE J. MUCHER. 

